CN101169476A - Multi-level precision automatic positioning technology in forest canopy and mountainous areas - Google Patents

Abstract

The invention discloses a multi-level precision automatic positioning technology for forest canopy and mountainous areas. The invention is under the condition of closed forest canopy, due to the canopy closed and the influence of terrain, the satellite signal received by DGPS is interfered, and the signal of the data transmission station fails, thus limiting the use of DGPS in mountainous areas, hilly areas and under the forest canopy. The application of this positioning technology uses compass and total station non-directional wires to assist positioning, that is, outside the closed forest, select an open area, use DGPS to measure and position the reference station, and based on this, in the closed forest Select the measuring point, use the compass and total station to locate without directional wire, according to the DGPS positioning result of the reference station, through the PDA programming design, automatically calculate the positioning result of each measuring point, and realize the blind area spatial positioning where the DGPS system fails.

Description

Multi-level precision automatic positioning technology in forest canopy and mountainous areas

1. Technical field

The invention relates to a forest positioning technology, in particular to a multi-level precision automatic positioning technology for forest canopy and mountainous areas.

2. Technical background

As a modern high-tech, Global Satellite Positioning System (GPS) has been widely used in forestry, agriculture, surveying and mapping, geology, mining, petroleum, civil engineering and other industries. Because GPS technology has real-time, dynamic, automatic and all-weather determination of three-dimensional position and operating speed Therefore, spatial positioning technology is needed for forest boundary positioning in forest resource survey and monitoring, navigation, positioning, map data update, accurate forest area monitoring, aerial afforestation, forest disease and pest monitoring, forest fire monitoring, forest boundary division, and resource management. , forest tenure division, forest certification, forest positioning experiments, sample point reset, and remote sensing data corresponding to ground surveys, etc.

There are many mountainous areas in my country's woodlands. Due to the influence of mountainous terrain, forest canopy, tree trunks and other interference factors, GPS positioning research in forests is subject to great limitations: positioning time is prolonged, positioning accuracy is reduced, and the reliability of positioning results is poor. In some cases, due to the shading of the forest area and the narrow sky in some small canyons, it is impossible to ensure that there are more than 4 satellites, thus forming a blind spot space positioning where the DGPS system fails. Traditionally, the method of increasing the GPS antenna or using a handheld device is used to solve the above problems. Problem, all of the above methods have their disadvantages:

①Elevate the GPS antenna so that it is positioned higher than the crown of the tree, but in some virgin forests, the height of the tree exceeds 100m, this method has great limitations;

②Handheld GPS receivers can only perform single-point positioning, and their real-time positioning accuracy is ±100m, which is far lower than the necessary accuracy of ±1m for forestry resources investigation management and environmental monitoring. Under the condition of transforming into a differential GPS receiver, when there is tree crown influence, the accuracy of the handheld GPS receiver will be further reduced and the time will be extended.

Therefore, due to the vastness of the forest and the complexity of the stand structure, there is an urgent need for multi-level precision and multi-level resolution positioning technology to be applied to forest positioning.

3. Contents of the invention

In order to overcome the many troubles and errors inevitably brought about by the prior art in the process of forest positioning, the purpose of the present invention is to provide a multi-level precision automatic positioning technology for forest canopy and mountainous areas.

The purpose of the present invention is achieved like this:

1. In mountainous areas, hilly areas and forest canopy occlusion conditions, when GPS cannot be used for positioning in the forest, use DGPS (Differential Global Positioning System) to measure the coordinates of the reference station in open areas and forested roadsides or use the coordinates of known points. The compass and the total station are used to locate the wire in the canopy forest.

2. The positioning method of the compass wire is as follows: first, place DGPS at the reference points at both ends of the wire to measure the coordinates of the reference point; then, measure the distance, azimuth, inclination and magnetic declination from the reference point to the target point by the compass, The coordinates of each target point in the forest are automatically calculated by the PDA in the way of non-directional wires.

3. The positioning method of the total station wire is as follows: first, place DGPS at the reference points at both ends of the wire to measure the coordinates of the reference point; then, the total station measures the distance from the reference point to the target point, the zenith distance, the horizontal angle, Inclination angle, the coordinates of the target point in the forest are automatically calculated by the PDA in the way of non-directional wires.

This invention has the following advantages:

①Based on DGPS, the compass and total station have no directional wire operation method to realize the complementary advantages, disadvantages and resource sharing of space positioning and land observation positioning, and solve the blind spot space positioning that cannot guarantee more than 4 satellites question.

②Real-time data storage and automatic processing are realized through PDA programming and calculation.

4. Description of drawings

The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

Figure 1 is a schematic diagram of a non-directional wire.

5. Specific implementation methods:

The multi-level precision automatic positioning technology of forest canopy mountain is different from the existing positioning technology, specifically:

(1) In the blind area where the DGPS system fails, select the open area and the roadside in the forest area to use DGPS to measure the reference point coordinates, as shown in Figure 1, select A and B points in the open area to establish a positioning reference station, and use DGPS to measure and locate. Get coordinates. When using a compass to measure, first, place a compass at point A, measure the side length of A1 with the line-of-sight measurement, and measure the magnetic azimuth of side A1 with the compass; then, move the instrument to point 1, and measure the distance between 1 and A , observe the length of the 12 sides and the magnetic azimuth of the 12 sides; repeat the above process until point B. By digital model: $\begin{array}{c}\mathrm{\Δ}{x}_{12}=S_{12}^0\cos (T_{12}^0+\mathrm{\Δ})\\ \mathrm{\Δ}{\mathrm{the\; y}}_{12}=S_{12}^0\sin (T_{12}^0+\mathrm{\Δ})\end{array}$ Calculate the coordinate difference between points 1 and 2, where T ₁₂ ⁰ is the average magnetic azimuth angle of sides 1 and 2, Δ is the magnetic declination in this area, and S ₁₂ ⁰ is the average length of sides 1 and 2. From the known coordinates of point A, plus the coordinate difference, the coordinates of each target point are obtained, and the target point positioning under the forest canopy and mountain conditions is completed. The above work is programmed by the PDA, automatically recorded, and automatically calculated.

(2) When using a total station for measurement, as shown in Figure 1, first, place the total station at 1 point to aim at point A, record the direction angle H _A , and the side length D ₁ of A1; aim at point 2, and record the direction angle H _2. Length of 12 sides D ₂ ; calculate horizontal angle β ₁ = H ₂ -H _A , then move to point 2, aim at point 1 and record direction angle H ₁ , aim at point 3, move stations to the end point in turn, and obtain each Side lengths D ₁ , D ₂ , ... D _n+1 and β ₁ , β ₂ , ... β _n . It can be assumed that the azimuth angle α _A1 ′=0 of the side coordinates of A1, the coordinates of point A X _A ′=Y _A ′=0, and the end point X _B ′, T _B ′ can be obtained, according to ${{\mathrm{\α}}_{\mathrm{AB}}}^{\′}=\mathrm{tg}\frac{Y_B^{\′}}{Y_B^{\′}},$ Obtain δ=α _AB ′-α _AB , and then obtain the true azimuth of each side α _i =α _i ′+δ; then obtain each side Δx _i and Δy _i according to α _i and D _i , and know from point A Coordinates, obtain the coordinates of the target point under the condition of forest canopy and mountain, and complete the positioning work. The above whole process is the automatic communication, recording and automatic processing of the data interface between the PDA and the total station.

Claims (3)

1. multipole precision localization method of forest canopy hilly land, it is characterized in that: block under the condition at mountain area, hills area and crown canopy, when using GPS can't implement to locate in the woods, utilize DGPS (differential Global Positioning System) at opening, roadside, forest zone measuring basis station coordinates or utilize the known point coordinate, adopt box compass, total powerstation in close-stand, to carry out the lead location.

2. the multipole precision localization method of forest canopy hilly land according to claim 1, it is characterized in that: wherein the compass traverse localization method is as follows: at first, settle DGPS at the reference point at lead two ends, record the reference point coordinate; Then, record distance, position angle, inclination angle, the magnetic declination of reference point, calculate the coordinate of each impact point in the woods by omnidirectional lead mode by PDA automatically to impact point by box compass.

3. the multipole precision localization method of forest canopy hilly land according to claim 1, it is characterized in that: wherein total powerstation lead localization method is as follows: at first, settle DGPS at the reference point at lead two ends, record the reference point coordinate; Then, record distance, zenith distance, horizontal angle, the pitch angle of reference point, calculate the coordinate of impact point in the woods by omnidirectional lead mode by PDA automatically to impact point by total powerstation.

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